Carat weight is the only standard measurement of the Four C's. One carat equals 1/5 of a gram or .007 of an ounce. Jewelers utilize extremely precise scales to weigh diamonds to hundredths of a carat. Each of these "hundredths" is referred to as a "point". So, a one carat diamond is the same thing as a 100-point diamond, just as a .50 carat diamond equates to a 1/2 carat or 50-point diamond.
Carat weight and diamond size are not the same. Size can actually be greatly affected by the cut. Distance in millimeters across the top of the diamond has a huge impact on how big a diamond appears. Once a diamond ring is set, it is viewed from the top. So, diamonds that have a wider top diameter may seem bigger than stones with a higher carat weight, but a smaller top surface area.
Unfortunately, much of a diamond's natural carat weight is lost when it is cut and polished. Oftentimes, a Gemologist decides where and how to cut a stone by taking cut, clarity, and color into account, sometimes to the detriment of the final weight of a stone.
When referencing diamonds, “ct” (carat) and “ctw” (carat total weight) refers to approximate carat total weight. For gemstones, “tgwt” refers to approximate total gem weight. Diamond weights are not exact and refer to both solitaire and multiple stone diamond jewelry. Here is a helpful list of the ranges for weight: 1/20ctw=0.04-0.08ctw; 1/15ctw=0.06-0.10ctw; 1/10ctw=0.08-0.13ctw; 1/8ctw=0.10-0.16ctw; 1/6ctw=0.13-0.20ctw; 1/5ctw=0.17-0.23ctw; 1/4ctw=0.22-0.28ctw; 1/3ctw=0.29-0.38ctw; 3/8ctw=0.34-0.44ctw; 1/2ctw=0.45-0.58ctw; 5/8ctw=0.57-0.69ctw; 3/4ctw=0.68-0.82ctw; 7/8ctw=0.80-0.95ctw; 1ctw=0.95-1.12ctw; 1-1/8ctw=1.08-1.20ctw; 1-1/4ctw=1.17-1.32ctw; 1-1/3ctw=1.28-1.39ctw; 1-3/8ctw=1.32-1.45ctw; 1-1/2ctw=1.41-1.59ctw; 1-5/8ctw=1.57-1.69ctw; 1-3/4ctw=1.65-1.83ctw; 1-7/8ctw=1.79-1.95ctw; 2ctw=1.92-2.13ctw; the same pattern continues for all larger diamond weights.
"Magic size" refers to .5, .75, and 1 carat stones. Reaching these optimal numbers greatly impacts a stone's value. For example, diamond rings with stones that weigh .48 carats are likely much less expensive than ones weighing .50 carats even though they appear to be almost identical. Hitting a "magic" 1/2, 3/4 or 1 carat sweet spot can lead to a big difference in price, but not much difference in the way the diamond ring looks for you. It’s something to consider when you’re shopping for the perfect stone.
Diamonds already set in jewelry cannot be weighed; so, carat weight is estimated by measuring a stone's outside dimensions. Appraisals or grading reports generally list carat weight measured under these conditions as approximate weight. If the jewelry contains multiple gemstones, the measurement is referred to as an approximate or estimated "total carat weight".
Most diamonds sold today are less than one carat. In fact, the average diamond engagement ring is less than .50 carats. And most people assume that the more a diamond weighs, the more it’s going to cost.
What most of us don't realize; however, is that this cost increase is not proportional to the increase in weight.
In fact, doubling the weight of a stone doesn't double the cost — if all other factors remain the same, it can quadruple the price tag! Avoid major price spikes in diamond rings by staying just below the "magic size". A .48 carat diamond looks identical to a .50 carat diamond, but it can be significantly less expensive. Similarly, a 1.48 carat diamond looks identical to a 1.5-carat diamond, but the 1.48 diamond will likely be noticeably cheaper.
To some people, the size of the diamond matters most. If this is the case, clarity and color grades may be adjusted to meet budget requirements. Be aware of finger size. Large diamonds may be too big for small fingers. If you're lucky enough to be buying a diamond engagement ring for someone with small hands, often medium or small stones will appear to be large on the wearer.
No matter which factor is the most important for choosing the right diamond, we can help you find the perfect one for you. We offer loose diamonds from 1/3 to 4 carats, plus a variety of pre-fashioned diamond rings in various weights.
Browse through our exquisite line of diamond jewelry, including diamond bracelets, pendants, necklaces, and earrings in an array of styles and sizes by a variety of fine jewelry designers.